A device which converts DC into AC, or AC into DC. For example, a chopper.

A device which changes the frequency of a signal. For instance, a frequency changer.

A device which changes computer input, data, files, media, programs, hardware, or systems, from one form to another. For example, an analog-to-digital converter, or a binary decoder.

A device, that connects to a TV, which decodes the incoming signal or otherwise enables viewing of certain channels or programming. Such a device is usually in the form of a box, and may also connect to another device, such as a VCR. Also called cable box (1).

A device, usually in the form of a box, which serves to tune a TV to all available channels. Also called cable box (2).